Acetonitrile → ethyl 1-ethyl-4-fluoro-1H-pyrazole-5-carboxylate

Temperature

100 °C

A microwave vial was charged with ethyl 1-ethyl-1H-pyrazole-5-carboxylate (0.2 g) and Selectfluor™ (0.548 g) followed by acetonitrile (3 ml) and acetic acid (0.5 ml). The mixture was heated at 100° C. under microwave irradiation for 120 min. Selectfluor™ (0.548 g) was added and the mixture was heated was heated at 100° C. under microwave irradiation for 60 min. The solvent was removed in vacuo and the residue was partitioned between DCM (15 ml) and water (15 ml) and separated by hydrophobic frit. The aqueous layer was washed with dichloromethane (2×5 ml) and the combined organic layers concentrated in vacuo. Purification by chromatography on silica gel (20 g silica cartridge) eluting with a gradient of 0-50% DCM in cyclohexane over 20 min gave the title compound (67 mg) as a colourless oil.

1. temperaturethe mixture was heated
2. temperaturewas heated at 100° C. under microwave irradiation for 60 min
3. customThe solvent was removed in vacuo
4. customthe residue was partitioned between DCM (15 ml) and water (15 ml)
5. customseparated by hydrophobic frit
6. washThe aqueous layer was washed with dichloromethane (2×5 ml)
7. concentrationthe combined organic layers concentrated in vacuo
8. customPurification by chromatography on silica gel (20 g silica cartridge)
9. washeluting with a gradient of 0-50% DCM in cyclohexane over 20 min

ORD record

ord-53283dd5af544aa19a3d3f9adc3942ad

Source dataset

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08658635B2